What is an online bidding fee?
An online bidding fee, sometimes called a platform fee or live bidding surcharge, is an extra charge some auction houses add when you bid through an online bidding platform instead of in the room.
Why it exists
Many auctions now run live online bidding through a third-party platform. Auction houses usually describe the extra fee as covering the cost of that service, and some pass it on to buyers who use it.
How much is it?
It varies a lot. In UK auction catalogues we checked, examples included 5% of the hammer price plus VAT and 4.95% plus VAT. Other houses charge less, charge nothing, or use flat fees by price band (Copart UK does this, as explained in our Copart guide). You'll find it in the conditions of sale, sometimes under "online bidding" or "supplementary fee".
What it does to your total
Take a £500 hammer price with a 20% premium plus VAT. Bid in the room and the total is £620. Bid online and add a 5% online fee, with VAT on that as well, and it becomes £650.
| Hammer price | £500.00 |
| Buyer's premium (20%) | £100.00 |
| Online bidding fee (5%) | £25.00 |
| VAT at 20% on the fees (£125.00) | £25.00 |
| Total to pay | £650.00 |
The same lot bid in the room costs £620, so the online fee adds £30.
It works like extra premium
Both percentages are charged on the hammer price, with VAT on top, so a 15% premium plus a 5% online fee costs exactly the same as a 20% premium. Treat the online fee as part of the rate you're really paying.
Ways to avoid or reduce it
- Check whether the auction house runs its own online bidding, which may not carry a platform fee.
- Bid in the room, by phone, or leave a commission bid directly with the auction house. Check whether those carry any charges of their own.
- If you do bid online, include the fee in the maximum you set. See how to work out your maximum bid.
How BidCalc helps
The Online bidding fee (%) box adds it as its own line, with VAT, so you can see exactly what it costs. Try the same bid with the box at 0% and at 5% to see the difference, or put the two routes side by side in the comparison tool.
See the £500 example Compare online vs in the roomGeneral information only, not tax or financial advice. Auction houses set their own fees and terms, so always check the conditions of sale and confirm the details with the auction house before you bid.